Pusher-Trailer: A Bicycle-Frame Solution

dbaker said:

Well done, KF I wondered how you would inject it and this way you made sure to get them completely full

Click to expand...

I still have 1/2 of a can left

Think of the trouble I could get into with this goop!

Alas - I think I will be delayed yet one more day waiting for this stuff to setup. I just hope it works for this is the last hurrah.
Worry wart, KF

Kingfish said:

I still have 1/2 of a can left

Click to expand...

Perhaps fill sacrificial plastic tubes of similar size to cut open later to assess cure progress.

(Similar to testing the remainder of a batch of epoxy)

Do not--I repeat--do not attempt to use cheap, hardware-store canned foam. This is not the same thing, and if injected into your chassis, will form a gummy mass that won't dry. Foamseal foam is a professional grade foam, which although it is a little unforgiving to cleanup mistakes, has superior mechanical properties and catalytic curing so it will dry even in an enclosed space."

Click to expand...

from here (among other places):

http://forums.vwvortex.com/showthread.php?2336573-Any-of-you-ever-foam-fill-your-frame-rails

TylerDurden said:

Kingfish said:

I still have 1/2 of a can left

Click to expand...

Perhaps fill sacrificial plastic tubes of similar size to cut open later to assess cure progress.

(Similar to testing the remainder of a batch of epoxy)

Click to expand...

I checked one of the bulbous bits and it is finally starting to cure deeper inside. Tore off a taped-over vent hole and it was still gooey. I have already done a preliminary clean-up job around the dropouts with my thumbnail; scrapes off the power-coated paint easily enough. At this point I have brought it inside where it is warmer. Maybe – just maybe I can get to this late tonight and finish the cleanup.

jonathanm said:

Do not--I repeat--do not attempt to use cheap, hardware-store canned foam. This is not the same thing, and if injected into your chassis, will form a gummy mass that won't dry. Foamseal foam is a professional grade foam, which although it is a little unforgiving to cleanup mistakes, has superior mechanical properties and catalytic curing so it will dry even in an enclosed space."

Click to expand...

from here (among other places):

http://forums.vwvortex.com/showthread.php?2336573-Any-of-you-ever-foam-fill-your-frame-rails

Click to expand...

Too late now; I yam committed - or should be possibly

The frame has a different tone and ring to it; duller. We like that.
Gooey to firm, KF

As a Pusher, this frame is not suitable for heavy load; light-to-medium loads are OK. However the design WAS for heavy load. The axial twisting results in the trailer steering the eBike into traffic or to the curb and oscillating without control.

Click to expand...

If you look at a commercial bob trailer the head tube is at least twice the length of the head tube on a regular bike. I think that has to help with the twisting or they wouldn't bother.

The Foam Treatment Results

It was messy. It was gooey. I have crap on my hands that won’t come off without peeling off the skin. I soaked my hands in Vitamin-E before bed and they look better than if they were run over by an ugly truck. However…

The axial wobble is gone! I just finished a weight test (partial success with frame being the winner) and the trailer frame has firmed up nicely. There is still a wobble, however it is a side-to-side wobble that is partly expected and is manageable. I took the exact same route as before and had vastly higher confidence with the setup; it was close to pleasure-sailing although there are caveats and pitfalls to beware of. I can still induce a side-to-side wobble from the handlebar if I am not careful, or if I try to dodge a pebble quickly; this causes the trailer to wobble side-to-side however if I let up on the throttle and stay calm it pulls itself out of it quickly. I had the Steering Dampener set pretty low, so I might try upping it a notch to see if that helps. But really – and completely I am here to certify that the fix was good, and the trailer frame is sturdy enough for cross-country.

It is possible that this trailer could be returned as a pusher-design. If I started over – I’d pick a steel frame, and probably still fill it with foam and use that two-part stuff that autobody people use; that’s the proper way to be sure.

Nnew pictures to show because the trailer will look exactly the same. The one thing that did change was the load-out: 6 batteries were removed from the ebike and put onto the trailer; it is now going to carry ½ of the original compliment. I also placed the batteries closer to the centerline to reduce the moment.

That’s about it for now; more will be posted on the other thread about the other half of the test that didn’t go so well.
Trailering, KF

Good news with the foam Do you think the foam is cured and adding stiffness, or just damping?

jonathanm said:

Good news with the foam Do you think the foam is cured and adding stiffness, or just damping?

Click to expand...

It might be doing both - at least that was the hope and intention. I haven't been on it for yet another day or two so I bet it is even more cured. I was attentive to keep the tubes open to the air so they could breathe and air out. It was m e s s y.

Batteries are loaded in the trailer now; fully charged - ready for the next test run. Here's a pic of my battery packaging:



The left side is used to mount/unmount the trailer batts quickly which makes management a dream; I can unload 75 lbs from that bike & trailer in about 5 minutes. Ortliebs use a metal brace; reused from last year to hold the batts in place. Saddle bags are on the right and they mount directly behind the steering column on top of the triangle.

Hoping tomorrow is a good day to die (er, forgive my Klingon optimism) :lol:
I'm ready Freddy, KF

@Kingfish-

Are you in San Francisco now? Cause Edward Lyen told me that you are coming down here and Let me know. We might meet you 8)

chroot said:

@Kingfish-

Are you in San Francisco now? Cause Edward Lyen told me that you are coming down here and Let me know. We might meet you 8)

Click to expand...

The Plan is to meet next Sunday August 14th at the Presidio at Noon. From there - we have been invited to ride north to Marin.

Best regards, KF

Kingfish said:

The only thing missing from this equation is the dragon tattoo :lol:

Click to expand...

Sorry, OT maybe, but I collect ebiker tattoos (found this while searching the EB (Ebikers Bible) for the phrase "dragon ebike" on an unrelated matter).

Aboard the Alt. Planet (ES) I recently posted a pic of my own newish tattoo:


Sooo, a dragon pic/tattoo plus ebike... Hope that counts! (I'm trying to collect the whole set.)
L

I was looking at a mtbs frame today thinking it would make a handy single wheel trailer if flipped upside down and saddle bags added

Anyhow its a old old thread but the OP's trailer has got my interest and now Im curious if flipping it upside down would fix its handling / wobble issue. The build has great potential.

What I noticed is its head tube angle is quite straight unlike the bob trailers angle which is angled leaning heavily forward.



I am thinking the reason behind the lean is the bob trailer folks worked out a handling issue by employing the heavy lean as depicted below on a old bob trailer



The bob trailer also uses a longer hitch tube Im not sure how this comes in to play but it may effect stability as the OP trailer seems to be lacking leverage in the hitch.
.


Below are a few photos of various single wheel trailers hitch tube angle.



There must be something to all this leaning forward business



Looks to be more then fashion to me
~~~

Tilting the steering axis forward makes the trailer lean more into the turn than the tow bike does.